Pressure operated switch



L. J. BORDELQN PRESSURE OPERATED swI'rcH Filed March 5, 1948 2 Sheets-Sheet 1 PRMURE GVIITCII :www T 12h. z

April 1s', 195o L. J. SORDI-:LON 2,504,381 PRESSURE OPERATED SWITCH Filed March 5, 1948 2 Sheets-Sheet 2 combus'riom fxunusr t uen-rm: soLwom VALVE gli 2 SWITCH Z2 F=| 'E C7 v nventor Gttorncg Patented Apr. 18, 1950 rarissima oraaa'ran swrrcn Lawrence J. Bordelon, San Diego, Calif., assignor to Consolidated Vnltee Aircraft Corporation,

San Diego, Calif.,

a corporation o! Delaware Application March 5, 194,8, Serial No. 13,273

(Cl. 20G-82) 18 Claims.

This invention relates to devices iorcontrolling electrical circuits and more particularly to circuit controlling devices automatically operable in response to variations in external conditions.

An object of the present invention lies in providing a novel form of pressure operated device for operating an electric switch automatically in response to external pressure conditions to control an electrical circuit.

Another object of the invention resides in the provision of an improved pressure operated electric circuit controlling device having indicating means associated therewith to denote the occurrence of a particular event.

A further object of the invention is to provide an improved form of electric circuit controlling device adapted to be automatically operated in response to a pressure condition and when operated being adapted to remain in its operative position, and having a manual reset element with the manual reset element being adapted to indicate when a switching operation has occurred.

A still further object of the invention is the provision of a simpliiied form oi' pressure operated electric circuit controlling device which is economical to construct and emcient and reliable in operation.

Other objects and features of the present invention will be readily apparent to those skilled in the art from the following specication and appended drawings wherein is illustrated a preierred form of the invention, and in which:

Figure l is a front elevational view of the circuit controlling device according to the present invention, but with the cover removed;

Figure 2 is a side elevational view;

Figure 3 is a horizontal sectional view taken on y the line III--III of Figure 2;

Figure 4, is a schematic view showing one use for the electric circuit controlling device of the present invention;

Figure 5 is a detail view illustrating in iront elevation the snap switch utilized in the invention Figure 6 is a schematic view illustrating another use of the present invention; and

Figure 7 is a diagrammatic View showing the circuits associated with the snap switch o1' Figure 4.

The pressure operated device I0, of the present invention, as illustrated in the drawings, embodies a substantially air-tight enclosing structure or housing consisting of a substantially recoi any light-weight material. such as aluminum, having a cover I2 mounted thereon and secured thereto as by a pair of studs I3 and a third stud I4. The pair of studs I3 are of suiilcient length to extend completely through base II and project beyond the exterior face thereof, whereby these projecting portions can accept a nut I5 and can be utilized to mount the pressure operated device It in a desired location. The base II comprises four wall portions I6, I'I, I8, and I9 which define a cavity or switch chamber 2|. Disposed within switch chamber 2|, and substantially centrally thereof, is a usual self-contained electric snap switch 22, of the micro-switch type. The switch 22 rests upon an insulating piece 23 and both are securely held to the base I I by a pair of mounting studs 2S which are threaded into the base ii.

The switch 22, as has been stated, is of usual construction and, as best shown in Figure 5, comprises a casing or insulating housing 25 which carries three conducting pieces 26, 27 and 28, with the conducting pieces 28 and 2l respectively being provided with stationaryl contact faces 30 and 3i to lie oppositely disposed and spaced from one another. The conducting piece 28 provides a terminal for the connection of a power lead 32 al.: by a terminal stud 29. A contact arm 33 is n ounted in casing 25 with one end thereof supi: orted upon the shorter leg of a generally L- shaped pivotal member 34. The longer leg of pivotal member 34 is pivotally supported by contact arm 28. The contact arm 33 includes an integral stamped thin tongue-like spring portion 35, the end oi which bears against conducting piece 28 for pivotal support thereon and to ilex spring portion 35 and place it in compression.

The contact arm 33 is made of a spring material whereby the stamped-out tongue-like portion 35 is adapted to have resilient characteristics. The free end of the contact arm 33 lies between the spacedstationary contacts '30 and 3| and carries contacts 36 and 3l on either side thereof which contacts are adapted to cooperate with the statangular, generally cup-shaped base II, formed tionary contacts 30 and 3| to make and break electrical circuits therethrough. The flexed spring portion 35 normally exerts its bias upon contact arm 33 to hold movable contact 31 in engagement with stationary contact 3|. An actuator or switch button 38 is slidably carried by casing 25 and engages the end of the shorter leg of generally L-shaped pivotal member 34 which supports one end of resilient arm 33. The bias of exed spring portion 35 is transmitted through pivotal member 34 to switch button 33 :,soassi a to hold it normally in the position shown in Figures l and 5. Movement of switch button Il rectilinearly into casing 2l will cause pivotal member ll to carry the supported end of contact arm 32 past the pivoted end of ilexed spring portion l5 whereupon the resilient force provided' by this portion It acts to move contact arm 22 l with a snap to disengage contacts 3i and l1 and to carry movable contact I. into engagement with stationary contact I.. Conducting leads Il and l2 are connected respectively to conducting pieces 28 and 21 as by the terminal studs 42. and run therefrom to a usual electric connecting plug Il which is secured to the exterior surface of wall Il of base Il by a plurality of studs 45. An insulating sheet Il is disposed within switch chamber 2| adjacent the switch 22, as shown.

It is understood that the particular construction of switch 22 forms no part of the present invention and the invention is not to be limited to the specic type illustrated, as any electric switch. of suitable size, having engageable and disengageable contacts adapted to be actuated to effect desired circuits is contemplated for use herein Mounted upon the housing 2l of switch 22 is a bracket member 41, rigidly secured in position by the switch mounting studs 2l. The bracket member 41 includes an elongate, resilient arm 4l which is normally parallel to and spaced from the bottom of switch housing 2l a distance equal to the amount that switch button 38 projects from casing 25. Arm 48 at its free end Il is adapted to abut switch button 2l but normally exerts no force thereon. At this same free end of arm It there is provided a depending portion Si which carries a iatching roller l2. -Roller 52 is adapted to be engaged and a force applied thereto by a longitudinally movable actuator or plungery element 52 carried by base I I, which force will move resilient arm I2 upwardly toward casing 2l to thereby move the switch button 32 to effect the operation of switch 22.

Plunger element I2, as shown in the drawings, comprises ridged portions Il at one end thereof which are provided for easein'grasping the plunger for manual movement thereof. a smooth-faced cylindrical portion It. an annular shoulder or flange 51, an annular groove S2. a camming ridge il, an annular groove i2 which serves as a detent means for roller 52. and a cylindrical portion 62, having a longitudinally extending recess I4 formed therein to lighten the mass of the plunger 53 to render it more readily movable when pressure is applied thereto.

The plunger element It is mounted on base Il for reciprocal movement within switch chamber 2i and lles disposed closely adiacent switch 22 and substantially parallel to the longitudinal axis thereof, and 4has its ridged end i! disposedexteriorly of the base, with the cylindrical portion 56, adjacent that end, being disposed in and movably carried by a smooth cylindrical bore 66 provided in wall i1. Flange 51, adjacent the cylindrical portion 5t, is engageable by the interior surface of wall I1 to determine the amount of rectilinear movement, outwardly of the housing, to be had by the plunger 5I. The cylindrical portion 63 provided at the opposite or interior end of plunger 53 is slidably received within a cylindrical bore 66 provided in a rectangular blocklike mass 61 formed integral with base Ii and extending from walls Il and II thereof into chamber 2|. Plunger 53 is thus mounted for longitudinal movement in base il by the disposition of the cylindrical portion It thereof in bore ll and the cylindrical portion in bore which as shown is axially aligned with bore It.

As shown. bore Il is provided with threads Il adjacent its opening 0l in wall i2 whereby an appropriate fitting may be secured for the introduction of gas, compressed air or other fluids into bore il. For the gas or air to pass from bore tt and into housing Il there' is provided a small bore 10 which connects bore tl with the interior of switch chamber 2 i.

A pin 1i is carried by block t1 and extends transversely through bore It to serve as a stop ble by the interior end of plunger 58 to limit the inward movement of plunger 52. It is here noted that stop 1l and flange 51, in addition to defining the amount of movement of plunger I3 within switch chamber 2i, prevents it from being inadvertently removed from the housing. Before plunger 52 can be removed, pin 1I must be pulled whereupon the plunger 5I could slide out of the housing through bore It.

In the normal or "oil' position of the present invention the plunger Il occupies the position shown in full line representation in Figures l and 3. Inl this position the cylindrical portion t2 of plunger 52 is positioned against stop 1I and shuts oi! access to the small connecting bore 1I. Itching roller 52 will lie in annular groove 58 and the switch button 32 occupies its full extended position.

Now with the application of pressure to the interior end of plunger l2, by the introduction of gas or air under pressure into bore 6B, plunger 53 will be made to move to the right, as viewed in Figures 1 and 2, to the dotted line position there shown. .The interior end of plunger it will move past bore 10 to uncover it and permit the iiow of the gas into the switch chamber 2|. In this movement oi plunger 52 to the right camming ridge ,will ride under roller 52 to move resilient arm ll upwardly toward switch 22 to carry switch button 2l into the housing to actu` ate switch arm 22 and eifect the engagement of movable contact It with stationary contact Il. As the camming ridge Il slides past roller l2 the latter will move downwardly under the bias of resilient arm 4l into a iatching position in detent groove 02. This last movement of roller 52 will not affect or disturb the engagement of contacts 2l and 3l, for the switch button Il will still be displaced a suilicient amount into housing 25 to maintain this desired switching condition. Plunger il will be maintained in its actuated or on" position by roller 52 which is held in detent groove 62 bythe resilient force of arm Il until such time manual force is applied to the exterior end of plunger il to reset it. The plunger 52 is colored or otherwise distinctively marked on that portion thereof which is normally disposed within the housing 25 whereby when it moves a part of the colored portion will come into view to provide a visual indication that it has been moved to its on position and that the switch 22 has been operated. To reset the present device it is necessary only to manually move the plunger Il inwardly into enclosing housing Il. roller 52 will ride over cam 6| and fall with a snap into annular groove 5l, and bore 1I will be closed by the cylindrical portion 63.

As illustrated the wall I1 of housing Il is provided with a bore 12 therethrough, the exterior opening thereof being normally closed by a circu-v lar seal 1I which may be a decalcomania or a paper disk with an adhesive backing. It is understood that the particular material comprising the seal forms no part of the invention; any material can be used which eects a readily tearable seal. The seal 'I3 is adapted to be ruptured or torn upon the introduction of a gas under pressure into the housing II which as has been stated is substantially air-tight so that the gas, to escape, must puncture seal 1l over bore 12. The seal 13 thus serves as an additional means of indicating that a pressure condition had occurred capable of eil'ecting actuation of plunger I and operation of switch 22. Seal 'I3 provides a more positive indicating means than plunger I3 and it is not necessary to rely solely on the position occupied by plunger l! as an indication of an operation, as plunger 53 may inadvertently be returned into the housing before interested personnel had had an opportunity to observe it. If plunger 53 remains in its outward or on position than a double check is had.

It is obvious that a: medium other than gas or air may be employed for operation of the present invention, a fluid such as oil could be provided: however, in this case the small bore Il is plugged and a usual seal applied in association with the plunger 53 to prevent entry of the oil into switch chamber 2 I. Of course with utilization of a liquid the benefit of the seal 13 as an indicating device is sacrificed. For the latter reason such uses are preferred in which a gaseous medium can be employed.

Figure 4 illustrates one use of the present invention in an aircraft re extinguishing system. The fire extinguishing system herein disclosed is understood to be a conventional one and is merely an exempliilcation of one use of the invention. As shown, this system comprises a main supply S0 of a fire extinguishing medium such as carbon dioxide gas contained under pressure in a pair of flasks 9| and 92 and a reserve supply S3 composed of a second pair of asks 8l and 95. Flasks SI and 92 are interconnected by suitable piping !i to a main distribution line Ol which leads to a usual three-way check valve 88 yfrom which the gas is led to the various aircraft compartments where a fire hazard might develop.

Flasks 94 and l5 are similarly interconnected and joined to the three-way check valve $8.

Associated with each of the flasks II, 82, S4 and 95 is a usual solenoid operated valve 99 which normally closes its flask, and which valves are adapted to be electrically operated from remotely located manually operable control switches (not shown). The electric release valves 99 associated with flasks 9| and 92 are operable in unison to e'ect simultaneous opening of such flasks to empty the main supply of the fire extinguishing medium. Solenoid operated valves 99 associated with flasks BI and S5 of the reserve supply similarly eifect simultaneous emptying of these flasks when desired.

It is intended that as the flasks 9| and 92 are opened that a, small proportion thereof instead of going to the discharge check valve ll, will be routed by way of suitable connecting piping IUI to the pressure operated device I0 of the present invention, the piping IUI being connected thereto at threaded bore 66. The device I0 is disposed in the immediate vicinity of the flasks to which it is connected. Similarly flasks 94 and 95 of the reserve supply are connected to a second pressure operated device III provided therefor. From each of the devices I0 an electrical connection |02 is made to an indicator light Il! disposed where a pilot may readily discern it. Thus as the various ilasks are emptied pressure will be applied to the plunger 53 of the associated pressure device Il to actuate it to operate the switch 22 therein and turn on the indicator light III! controlled thereby. Latching roller 52 will maintain plunger B2 in its operated position and thus the associated light |03 remains lit. Because of this steadily burning light the pilot will know exactly when the main supply of ilre extinguishing medium has been blown and can then use his reserve supply as required. If the control valves 88 stick or jam and no light comes on when he actuates the main supply control switch he can immediately throw on his reserve supply. The gas introduced into switch chamber 2I will further rupture seal I3 and an indication is given at the device III itself that the asks have emptied.

The pressure device I0 aords a means for readily ascertaining when a flask is full preparatory to taking oil' on a flight. Ordinarily to determine the condition of a flask it must be weighed, as the weight of the flask both full and empty is known. It is obvious that removing each individual flask and weighing it is a time consuming operation. With the present invention it is necessary only to check first whether the indicating light |03 is on. If the light is on he knows the flasks associated therewith have been blown. However, if the light |03 is not on, since power to the light may be cut ofi be-` cause of the aircraft being on the ground, or for other reasons, he makes his second check at the pressure device I0 provided in the immediate vicinity of the flasks, which device is viewed to determine if the seal 'I3 thereon is ruptured.

If it is, then the mechanic knows that the asks associated with that pressure device have blown and that new flasks should be inserted in the holders and the device l0 reset. The time involved in making these visual checks is obviously very much less than the time required to remove and weigh the flasks, which in some aircraft amounts to several hours. Since fire is, without saying, much feared aboard an aircraft, a device similar to the present invention which has so many checks upon itself is extremely desirable for use in the fire extinguishing system to denote the condition thereof prior to taking the aircraft into the air, and when in the air, to indicate when the pairs of flasks have been emptied.

The pressure device III of the present invention may also be employed as a control device in an aircraft heating system as illustrated in Figure 6. This heating system, as shown, comprises a conventional internal combustion. type heater III having a contained combustion chamber therein for heating air passed thereover to be supplied to the cabin of an airplane. The fuel for the heater I I0 is provided thereto through a fuel line II I, which fuel line I I I has associated therewith a solenoid valve I I2 which controls the passage of fuel through the fuel line. An air intake duct ||3 is connected to the combustion heater III) to provide air for the combustion process therein and to provide air which passes over the combustion chamber to be heated thereby so that it may be used in the cabin.

An electrical connection IIS connects switch 22 in pressure device I0 with solenoid valve II2. Another electrical connection |I6 interconnects the switch 22 and a warning light II`| located in the pilots compartment. A third electrical lead IIS connects to a conventional on-oil switch asoasei 7 III and a source of powerI lli. It is here noted that solenoid valve electrical lead lil is electrically connected to conducting piece Il and contact Il of switch 22, warning light lead Il'l is connected into conducting piece Il and contact Il, and power lead il! is electrically connected to conducting piece 2t and movable contact arm Il. Thus in the normal position of pressure device |0 with movable contact 31 in cent with stationary contact Il, a circuit will be oompleted from power source ill to solenoid valve H2 upon operation of switch ill to its on position. This will open solenoid valve H2 to permit the flow of fuel to the combustion heater Ilii for operation thereof. In the operation of combustion heaters, if trouble develops therein a back-fire wiil usually occur which back-nre creaies a pressure condition in the air intake duct IIS. A defective combustion heater is a flre hazard and if permitted to stay in operation could exiplode or spout flame in some manner and thereby endanger the aircraft. The pressure device i0 provided by the present invention is adapted to obviate this fire hazard. On the occurrence of a. back-fire in the air-intake duct III, air under pressure will pass through conduit ill to enter pressure switch lo by way of bore t and actuate plunger 53, the movement of which operates switch button 38 to move contact arm Il to disengage movable contact 31 from stationary contact 3| to break the circuit to the solenoid valve I I2, permitting it to close fuel line I I i and thereby cut off the now of fuel to combustion heater i i0 to inactivate it. The movement of contact arm 33 in addition to breaking the solenoid valve circuit, effects engagement of movable contact 36 with stationary contact 30 to complete a circuit to the warning light Ill to indicate to the pilot that a combustion 4heater is defective and has been taken out of operation. At the time that a mechanic prepares to repair the defective combustion heater he can determine definitely which of the several heaters carried by the aircraft is the defective heater by observing which of the pressure switch devices I0 bears a ruptured seal 1I and the position of its plunger U. The heater, associated with the pressure device Il. can then be repaired, the pressure device I0 reset, and a new seal 1I applied.

It is here noted that the two examples described illustrate how the switch 22 can be made to perform a single electrical operation or two electrical operations. The fire extinguishing system of Figure 5 illustrates the use of but one of the two available circuits through switch 22, since the circuit which could be made by the engagement of contacts Il and I1 is not required. The heating system of Figure 6 requires two electrical devices to be controlled and therefore employs both the circuit controlled by contacts 3i and 31 and the circuit controlled by contacts I0 and 36.

It is, of course, obvious that the examples provided and described herein are merely for the purpose of exemplifying and illustrating the manner of operation of the pressure switch device i0 of the present invention.

While certain preferred embodiments of the invention have been specifically disclosed. it is understood that the invention is not limited thereto as many variations will be readily aption is to be given its broadest possible interpretation within the terms of the following mima. l

parent to those skilled in the art and the inven- I claim: l. In a pressure switch, an enclosure having an opening therethrough leading from the interior of the enclosure to the exterior thereof,

means to seal said opening, an electric circuit controlling device mounted within said enclosure. means responsive to a pressure condition movabLv mounted on said enclosure, and means operatively connecting said pressure responsive means with said electric circuit controlling device for effecting the operation of the latter upon movement of the former. said enclosure having an opening providing access from the exterior to the pressure responsive means whereby a gaseous medium under pressure may be introduced to act upon said pressure responsive means to move it to operate said electric circuit controlling device. said pressure responsive means adapted normally to occupy a position blocking communication into the .interior of the enclosure and adapted to be moved by said gaseous medium to unblocking position to permit entrance of the gaseous medium into the interior of the enclosure to dislodge said sealing means to uncover said flrst mentioned opening and provide a visual indication that an operation of the electric circuit controlling device has occurred.

2. In a pressure switch. 'a housing having a plurality of walls, one of said walls having an opening therethrough leading from the interior of the enclosure to the exterior thereof, means to seal said opening, said sealing means being formed of a material that is readily tearable, an electric circuit controlling device mounted within said housing, means responsive to a pressure condition movably mounted on said housing, means providing an operative connection between said pressure responsive means and said electric circuit controlling device for effecting the operation of the latter upon movement of the former, said housing having anopening therein affording access from the exterior to the pressure responsive means whereby a gaseous medium under pressure may be introduced to act upon said pressure responsive means to move it to operate said electric circuit controlling device, said pressure responsive means adapted normally to occupy a position blocking communication between said access opening and the interior of the enclosure and adapted to be moved by said gaseous medium to unblocking position to permit entrance of the gaseous medium into the interior of the enclosure to provide pressure therein.

3. In a pressure switch, an enclosure having an opening therethrough leading from the interior of the enclosure to the exterior thereof, means comprised of a readily tearable material to seal said opening, an electric circuit controlling device mounted within said enclosure, means responsive to a pressure condition movably mounted within said enclosure and adapted to extend from the interior of the enclosure to the exterior' thereof, and means providing an operative connection between said pressure responsive means and said electric circuit controlling device whereby the latter may be operated upon movement of the former, said enclosure having an opening affording .access from the exterior to the pressure responsive means whereby a gaseous medium under pressure may be introduced to act upon said pressure responsive means to move it to operate said electric circuit controlling device, said enclosure having an opening providing communication between said access openingand the interior of the enclosure. said pressure responsive means adapted normally to occupy a position blocking entrance to this opening and adapted to be moved by said gaseous medium to unblocking position to permit ilow of the gaseous element from the access opening through the communicating opening and into the interior of the enclosure to provide a pressure therein to tear said sealing means to uncover said rst mentioned opening, movement of said pressure responsive means by` said gaseous medium causing a portion of the pressure responsive means to be displaced from a position within said enclosure to a position exteriorly thereof, said displaced portion and said torn sealing means providing a visual indication that an operation of the electric circuit controlling device has occurred.

4. In a .pressure switch, a housing, a self-contained electric switching means mounted within said housing, said self-contained electric switching means comprising a casing, relatively movable circuit controlling means therein, and a movable actuator for said means extending from within said casing to the exterior thereof, means responsive to apressure condition slidably mounted for rectilinear movement on said housing and operative to move said actuator to operate said electric switching means, said housing having an opening therein whereby a gaseous medium under pressure may be introduced therein to move said pressure responsive means rectilinearly to move said actuator to operate said electric switching means, and means engageable with said pressure responsive means to hold it in the position to which it has been moved.

5. In a .pressure switch, a housing having aligned openings therein, a self-contained electric circuit controlling device mounted within said housing, said self-contained electric circuit controlling device comprising a casing, relatively movable contacts therein, and a movable actuator for said contacts extending from within said casing to the exterior thereof, an elongate member mounted within said aligned openings for support thereon and being rectilinearly movable therein in response to a. pressure condition, an elongate resilient member having one end free and the opposite end ilxedly supported providing an, operative connection between said pressure responsive elongate member and the actuator of said electric circuit controlling device for effecting the operation thereof, and latching means carried by the free end of said elongate resilient member engageable with said pressure responsive elongate member to releasably maintain it in the position to which it is moved.

6. In a pressure switch, a housing comprising wall portions, one oi' said wall portions having an opening therethrough, a self-contained electric circuit controlling device mounted within said housing, said self-contained electric circuit controlling device comprising a casing, relatively movable contacts therein, a movable actuator for said contacts extending from within said casing to the exterior thereof, a ledge portion within said housing having an opening therethrough and in alignment with said rst opening, an elongate member slidably mounted within said aligned openings to be supported thereby and being rectilinearly movable therein in response to a pressure condition, an elongate resilient actuating member having one end free and the opposite end fixedly supported providing an operative connection between said electric circuit controlling device and said elongate member, a camming means on said elongate member for moving said actuating member on rectilinear movement of the elongate member to move said contacts actuator to operate said electric circuit controlling device, and latching means carried by the free end ot Said elongate member releasably to maintain it in the position to which it has been moved.

7. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing, a ledge portion within said housing having an opening therethrough in alignment with said iirst opening, and opening to the exterior and through which opening a gaseous medium under pressure may be introduced within said housing, an elongate member slidably mounted within said aligned opening to be supported thereby and being rectilinearly movable therein in response to a pressure condition, an actuating member for operating said electric circuit controlling device and engageable by said elongate member, and a camming portion on said elongate member for moving said actuating member, on rectilinear movement of the elongate member, to operate said electric circuit controlling device, said elongate member having detent means cooperating with said actuating member for releasably maintaining said elongate member in the position to which it is moved and maintaining said actuating member in operating position.

8. In a pressure switch, a housing having aligned openings therein through one of which a gaseous medium under pressure may be introduced within said housing, an electric circuit controlling device mounted within said housing, an elongate member slidably mounted within said aligned openings to be supported thereby and being rectilinearly movable therein in response to a pressure condition, a resiliently mounted actuating means for operating said electric circuit controlling device and engageable by said elongate member, and a camming portion on said elongate member for moving said actuating means, on rectilinear movement of the elongate member, to operate said electric circuit controlling device, said elongate member having groove means therein adapted to receive said actuating member to maintain said elongate member in the position to which it is moved and to maintain said actuating member in its operating position.

9. In a pressure switch, a housing having aligned openings therein, an electric circuit controlling device mounted within said housing, an elongate member slidably mounted within said aligned openings to be supported thereby, and being rectilinearly movable therein in response to a pressure condition, an actuating means for operating said electric circuit controlling device comprising a roller means and a resilient supporting means therefor Iexerting its bias to maintain said roller means in engagement with said elongate member, said elongate member having a pair of peripheral grooves formed on the exterior thereof and adapted alternately to receive said roller means to releasably restrain said elongate member, said grooves being separated bya camming portion over which said roller means rides on rectilinear movement of the elongate member to operate said electric circuit controlling device.

10. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housvin said housing, said opening being in alignment with said first opening and being adapted to support one end oi an elongate member the other end of which is supported by said first opening, which elongate member is rectilinearly movable in response to a pressure condition, an actuating means for operating said electric circuit controlling device disposed between said elongate 'member and said electric circuit controlling device and comprising a roller means carried by a resilient supporting means which exerts its bias to maintain said roller means in engagement with said elongate member, said elongate member having a pair of peripheral grooves formed on the exterior thereof and-adapted alternately to receive said roller means to releasably restrain said elongate member, said grooves being separated by a camming portion over which said roller means rides on rectilinear movement of the elongate member to operate said electric circuit controlling device.

11. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing, a ledge portion within said housing having an opening therethrough and in augment with said first opening, an elongate member slidably mounted within said aligned openings, to be supported thereby and being rectilinearly movable therein in response to a pressure condition. a pair of spaced stop means associated with said elongate member to determine the extent of rectilinear movement, back and forth, oi' said elongate member within said housing, said pair of stop means comprising a flange portion on said elongate member engageable by a wall of said housing and apin means disposed transversely within said opening in said ledge portion, an actuating member providing an operative connection between said electric circuit controlling device and said elongate member, and a camming means on said elongate member for moving said actuating member, on rectilinear movement oi the elongate member, to operate said electric circuit controlling device.

12. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing, a ledge portion within said housing having an opening therethrough leading to the exterior of the housing and in alignment with said first opening. and through which opening a gaseous medium under pressure may be introduced within said housing, an elongate memb`er mounted within said aligned openings to be supported thereby and being rectilinearly movable therein in response to a pressure condition, a pair of spaced stop means associated with said elongate member to determine the extent of rectilinear movement, back and forth, of said elongate member within said housing, said pair of stop means comlinear movement of the elongate member, to operate said electric circuit controlling device, said actuating member having latching means cooperating with said elongate member for releasably maintaining said elongate member in the position to which it is moved and maintaining said actuating member in operating position.

13. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing, a ledge portion within said housing having an opening therethrough leading to the exterior and in alignment with said first opening, and through which opening a gaseous medium under pressure may be introduced within said housing, an elongate member slidably mounted within said aligned openings to be supported thereby and being rectilinearly movable therein in response to a pressure condition, an actuating member for operating said electric circuit controlling device and engageable by said elongate member, and a camming portion on said elongate member for moving said actuating member, on rectilinear movement of the elongate member, to operate said electric circuit controlling device, a portion of said elongate member being normally positioned within the housing and displaceable to a position exteriorly thereof under the pressure of said gaseous medium to provide a visual indication that an operation of the electric circuit controlling device has occurred, said actuating member having latching means cooperating with said elongate member for releasably maintaining said elongate member in the position to which it is moved.

14. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted `within said housing, a ledge portion within said housing having an access opening therethrough leading to the exterior and in alignment with said first opening, and through which access opening a gaseous medium under pressure may be introduced within said housing, an elongate member slidably mounted within said aligned opening to be supported thereby and being rectilinearly movable therein in response to a pressure condition, an actuating member for operating said electric circuit controlling device and engageable by said elongate member, a camming portion on said elongate member for moving said actuating member, on rectilinear movement of the elongate member, to operate said electric circuit controlling device, said actuating member having latching means cooperating with said elongate member for maintaining said elongate member in the position to which it is moved, said housing having an escape opening therethrough leading from the interior to the exterior thereof, and sealing means normally to close said escape opening, said pressure responsive elongate member adapted normally to occupy a position blocking communication between said access opening and the interior of the housing and adapted to be moved by said gaseous medium to unblocking position to permit introduction of said gaseous medium under pressure into the interior of the housing to dislodge said sealing means to uncover said escape opening and provide a visual indication that an operation of the electric circuit controlling device has occurred.

15. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing. a ledge portion within said housing having an access opening therethrough leading to the exterior and in alignment with said first opening, and through which access opening a gaseous medium under pressure may be introduced within said housing, an elongate member slidablv mounted within said aligned opening to be supported thereby and being rectilinearly movable therein in response to a pressure condition, an actuating member for operating said electric circuit controlling device and engageable by said elongate member, and a camming portion on said elongate member for moving said actuating member, on rectilinear movement of the elongate member, to operate said electric circuit controlling device, said actuating member having latching means cooperating with said elongate member for maintaining said elongate member in the position to which it is moved, said housing having an escape opening therethrough leading from the interior to the exterior thereof, and sealing means comprised of a readily tear able material to seal said escape opening, which sealing means is adapted to tear on introduction of the gaseous medium under pressure into the housing to uncover this opening and provide a visual indication that an operation of the electric circuit controlling device has occurred.

16. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing, a ledge portion within said housing having an access opening therethrough leading to the exterior and in alignment with said first opening, and through which access opening a gaseous medium under pressure may be introduced within said housing, an elongate member slidably mounted within said aligned openings to be supported thereby and being rectilinearly movable therein in response to a pressure condition, an actuating member for operating said electric circuit controlling device and engageable by said elongate member, a camming portion on said elongate member for moving said actuating member, on rectilinear movement of the elongate member, to operate said electric circuit controlling device, said actuating member having latching means cooperating with said elongate member for maintaining said elongate member in the position to which it is moved, a portion oi' said elongate member being normally positioned within the housing and displaceable to a position exteriorly thereof under the pressure of said gaseous medium, said housing having an escape opening therethrough leading from the interior to the exterior thereof, and sealing means comprised of a readily tearable material to seal said escape opening, said pressure responsive elongate member adapted normally to occupy a position blocking communication between said access opening and the interior of the housing and adapted to be moved by said gaseous medium to unblocking position to permit introduction of the gaseous medium under pressure into the interior of the housing to tear said sealing means to uncover said escape opening, said displaced portion and said torn sealing means providing a visual indication that an operation of the electric circuit controlling device has occurred.

17. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing, a ledge portion within said housing having an access opening therethrough leading to the exterior and in alignment with said iirst opening, and through which access opening a gaseous medium under pressure may be introduced within said housing, an elongate member slidably mounted within said aligned openings to be supported thereby and being rectilinearly movable therein in response to a pressure condition, an actuating member for operating said electric circuit controlling device comprising a rollerv means carried by a resilient supporting means which exerts its bias to maintain said roller means in engagement with said elongate member, said elongate member having a pair of peripheral grooves -iormed therein and adapted alternately to receive said roller means to releasably restrain said elongate member, said grooves being separated by a camming portion over which said roller means rides on rectilinear movement of the elongate member, to operate said electric circuit controlling device, a portion of said elongate member being normally positioned Within the housing and displaoeable to a position exteriorly thereof under the pressure of said gaseous medium, said housing having an escape opening therethrough leading from the interior to the exterior thereof, and sealing means comprised of a readily tearable material to seal said escape opening, said pressure responsive elongate member adapted normally to occupy a position rblocking communication between said access opening and the interior of the housing and adapted to be moved by said gaseous medium to unblocking position to permit introduction of the gaseous medium under pressure into the interior of the housing to tear said sealing means to uncover said escape opening, said displaced portion and said torn sealing means providing a visual indication that an operation of the electric circuit controlling device has occurred.

18. In a pressure switch, a housing comprising wall portions, one of said wall portions having an opening therethrough, an electric circuit controlling device mounted within said housing, a ledge portion within said housing having an access opening therethrough leading to the exterior and in alignment with said first opening, and through which access opening a gaseous medium under pressure may be introduced within said housing, an elongate member slidably mounted within said aligned openings to be supported thereby and being rectilinearly movable therein in response to a pressure condition, a pair of spaced stop means associated with said elongate member to determine the extent of rectilinear movement, back and forth, of said elongate member within said housing, said pair of stop means comprising a iiange portion on said elongate member engageable by a wall of said housing and a pin means disposed transversely within said opening in said ledge portion, an actuating member for operating said electric circuit controlling device comprising a roller means carried by a resilient supporting means which exerts its bias to maintain said roller means in engagement with said elongate member, said elongate member having a pair of peripheral grooves formed therein and adapted alternately to receive said roller means to releasably restrain said elongate member, said grooves being separated by a camming portion over which said roller means rides on rectilinear movement of the elongate member, to operate sogni said electric circuit controlling device, a portion oi said elongate member being normally positioned within the housing and displaceable to a position exteriorly thereof under the pressure o( sealing means to uncover said escape opening, i

said displaced portion and said torn sealing means providing a visual indication that an operation ot the electric circuit controlling desaid gaseous medium, said housing having an 5 vice has occurred.

escape opening therethrough leading from the interior to the exterior thereof, and sealing means comprised oi' a readily tearable material to seal said escape opening, said pressure re- LAWRENCE J. BORDELON.

REFERENCES CITED 590ml elongate member adapted normally to 10 The following references are oi record in the occupy a position blocking communication between said access opening and the interior o1' the housing and adapted to be moved by said gaseous medium to unblocking position to permit insure into the interior of the housing to tear said file ot this patent:

UNITED STATES PATENTS Number Name Date 1,646,882 Schwinn Oct. 25, 1927 1,881,710 Lasweli Oct. 11, 1932 

